Remove pre 1.36 backwards compatibility code

build.rs

@@ -1,7 +0,0 @@
-fn main() {
-    let cfg = autocfg::new();
-    if cfg.probe_rustc_version(1, 34) {
-        println!("cargo:rustc-cfg=has_sized_atomics");
-        println!("cargo:rustc-cfg=has_checked_instant");
-    }
-}

core/build.rs

@@ -1,9 +0,0 @@
-fn main() {
-    let cfg = autocfg::new();
-    if cfg.probe_rustc_version(1, 34) {
-        println!("cargo:rustc-cfg=has_sized_atomics");
-    }
-    if cfg.probe_rustc_version(1, 36) {
-        println!("cargo:rustc-cfg=has_maybe_uninit");
-    }
-}

core/src/lib.rs

@@ -56,7 +56,6 @@
     feature(thread_local, checked_duration_since)
 )]
 
-mod maybe_uninit;
 mod parking_lot;
 mod spinwait;
 mod thread_parker;

core/src/maybe_uninit.rs

@@ -1,41 +0,0 @@
-//! This module contains a re-export or vendored version of `core::mem::MaybeUninit` depending
-//! on which Rust version it's compiled for.
-//!
-//! Remove this module and use `core::mem::MaybeUninit` directly when dropping support for <1.36
-#![allow(dead_code)]
-
-#[cfg(has_maybe_uninit)]
-pub use core::mem::MaybeUninit;
-
-#[cfg(not(has_maybe_uninit))]
-use core::mem::ManuallyDrop;
-
-/// Copied from `core::mem::MaybeUninit` to support Rust older than 1.36
-#[cfg(not(has_maybe_uninit))]
-pub union MaybeUninit<T: Copy> {
-    uninit: (),
-    value: ManuallyDrop<T>,
-}
-
-#[cfg(not(has_maybe_uninit))]
-impl<T: Copy> MaybeUninit<T> {
-    #[inline]
-    pub fn uninit() -> MaybeUninit<T> {
-        MaybeUninit { uninit: () }
-    }
-
-    #[inline]
-    pub fn as_ptr(&self) -> *const T {
-        unsafe { &*self.value as *const T }
-    }
-
-    #[inline]
-    pub fn as_mut_ptr(&mut self) -> *mut T {
-        unsafe { &mut *self.value as *mut T }
-    }
-
-    #[inline]
-    pub unsafe fn assume_init(self) -> T {
-        ManuallyDrop::into_inner(self.value)
-    }
-}

core/src/thread_parker/cloudabi.rs

@@ -5,11 +5,10 @@
 // http://opensource.org/licenses/MIT>, at your option. This file may not be
 // copied, modified, or distributed except according to those terms.
 
-use crate::maybe_uninit::MaybeUninit;
 use cloudabi as abi;
 use core::{
     cell::Cell,
-    mem,
+    mem::{self, MaybeUninit},
     sync::atomic::{AtomicU32, Ordering},
 };
 use std::{convert::TryFrom, thread, time::Instant};

core/src/thread_parker/mod.rs

@@ -51,7 +51,7 @@ pub trait UnparkHandleT {
 }
 
 cfg_if! {
-    if #[cfg(all(has_sized_atomics, any(target_os = "linux", target_os = "android")))] {
+    if #[cfg(any(target_os = "linux", target_os = "android"))] {
         #[path = "linux.rs"]
         mod imp;
     } else if #[cfg(unix)] {
@@ -60,7 +60,7 @@ cfg_if! {
     } else if #[cfg(windows)] {
         #[path = "windows/mod.rs"]
         mod imp;
-    } else if #[cfg(all(has_sized_atomics, target_os = "redox"))] {
+    } else if #[cfg(target_os = "redox")] {
         #[path = "redox.rs"]
         mod imp;
     } else if #[cfg(all(target_env = "sgx", target_vendor = "fortanix"))] {

core/src/thread_parker/unix.rs

@@ -5,10 +5,12 @@
 // http://opensource.org/licenses/MIT>, at your option. This file may not be
 // copied, modified, or distributed except according to those terms.
 
-use crate::maybe_uninit::MaybeUninit;
-use core::cell::{Cell, UnsafeCell};
 #[cfg(any(target_os = "macos", target_os = "ios"))]
 use core::ptr;
+use core::{
+    cell::{Cell, UnsafeCell},
+    mem::MaybeUninit,
+};
 use libc;
 use std::{
     thread,

core/src/thread_parker/windows/keyed_event.rs

@@ -5,8 +5,10 @@
 // http://opensource.org/licenses/MIT>, at your option. This file may not be
 // copied, modified, or distributed except according to those terms.
 
-use crate::maybe_uninit::MaybeUninit;
-use core::{mem, ptr};
+use core::{
+    mem::{self, MaybeUninit},
+    ptr,
+};
 use std::{
     sync::atomic::{AtomicUsize, Ordering},
     time::Instant,

src/once.rs

@@ -6,25 +6,16 @@
 // copied, modified, or distributed except according to those terms.
 
 use crate::util::UncheckedOptionExt;
-#[cfg(has_sized_atomics)]
-use core::sync::atomic::AtomicU8;
-#[cfg(not(has_sized_atomics))]
-use core::sync::atomic::AtomicUsize as AtomicU8;
 use core::{
     fmt, mem,
-    sync::atomic::{fence, Ordering},
+    sync::atomic::{fence, AtomicU8, Ordering},
 };
 use parking_lot_core::{self, SpinWait, DEFAULT_PARK_TOKEN, DEFAULT_UNPARK_TOKEN};
 
-#[cfg(has_sized_atomics)]
-type U8 = u8;
-#[cfg(not(has_sized_atomics))]
-type U8 = usize;
-
-const DONE_BIT: U8 = 1;
-const POISON_BIT: U8 = 2;
-const LOCKED_BIT: U8 = 4;
-const PARKED_BIT: U8 = 8;
+const DONE_BIT: u8 = 1;
+const POISON_BIT: u8 = 2;
+const LOCKED_BIT: u8 = 4;
+const PARKED_BIT: u8 = 8;
 
 /// Current state of a `Once`.
 #[derive(Copy, Clone, Eq, PartialEq, Debug)]

src/raw_mutex.rs

@@ -6,20 +6,14 @@
 // copied, modified, or distributed except according to those terms.
 
 use crate::{deadlock, util};
-#[cfg(has_sized_atomics)]
-use core::sync::atomic::AtomicU8;
-#[cfg(not(has_sized_atomics))]
-use core::sync::atomic::AtomicUsize as AtomicU8;
-use core::{sync::atomic::Ordering, time::Duration};
+use core::{
+    sync::atomic::{AtomicU8, Ordering},
+    time::Duration,
+};
 use lock_api::{GuardNoSend, RawMutex as RawMutex_};
 use parking_lot_core::{self, ParkResult, SpinWait, UnparkResult, UnparkToken, DEFAULT_PARK_TOKEN};
 use std::time::Instant;
 
-#[cfg(has_sized_atomics)]
-type U8 = u8;
-#[cfg(not(has_sized_atomics))]
-type U8 = usize;
-
 // UnparkToken used to indicate that that the target thread should attempt to
 // lock the mutex again as soon as it is unparked.
 pub(crate) const TOKEN_NORMAL: UnparkToken = UnparkToken(0);
@@ -29,10 +23,10 @@ pub(crate) const TOKEN_NORMAL: UnparkToken = UnparkToken(0);
 pub(crate) const TOKEN_HANDOFF: UnparkToken = UnparkToken(1);
 
 /// This bit is set in the `state` of a `RawMutex` when that mutex is locked by some thread.
-const LOCKED_BIT: U8 = 0b01;
+const LOCKED_BIT: u8 = 0b01;
 /// This bit is set in the `state` of a `RawMutex` just before parking a thread. A thread is being
 /// parked if it wants to lock the mutex, but it is currently being held by some other thread.
-const PARKED_BIT: U8 = 0b10;
+const PARKED_BIT: u8 = 0b10;
 
 /// Raw mutex type backed by the parking lot.
 pub struct RawMutex {

src/util.rs

@@ -34,10 +34,5 @@ unsafe fn unreachable() -> ! {
 
 #[inline]
 pub fn to_deadline(timeout: Duration) -> Option<Instant> {
-    #[cfg(has_checked_instant)]
-    let deadline = Instant::now().checked_add(timeout);
-    #[cfg(not(has_checked_instant))]
-    let deadline = Some(Instant::now() + timeout);
-
-    deadline
+    Instant::now().checked_add(timeout)
 }